Wireless power supply technology can wirelessly transmit power between electronic devices and is therefore widely used in consumer electronics and other types of electronic products. Current mainstream technology uses electromagnetic induction or magnetic resonance for energy transmission. It contains an energy transmitting terminal and several energy receiving terminals. The transmitting terminal converts the power into an alternating electromagnetic field to propagate in free space. When a receiving terminal is placed in the alternating electromagnetic field, it will generate the power by sensing the alternating electromagnetic field, thus enabling the energy to be transmitted in the free space. The wireless power supply technology eliminates the need for connection conductive wires between power consumption equipment and power supply device and power supply interface on the power consumption equipment, which can make the power supply safer, more reliable, and tidy. It has been widely used in electric tools, smart watches, smart bracelets and other electronic devices.
At present, the Airfuel Alliance adopts a separate Bluetooth device to achieve a two-way communication between wireless power transmitting terminal and wireless power receiving terminal. This allows one transmitting terminal to communicate with N receiving terminal simultaneously, and thus obtains the number and charging state of the wireless power receiving terminals. However, it requires adding Bluetooth devices at both transmitting side and receiving side, which will significantly increase the cost of the hardware.